<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>浮动练习</title>
    <style>
        div {
            width: 500px;
            border: 1px solid aquamarine;
            margin: 5px;
        }

        .box1,
        .box2,
        .box3 {
            width: 100px;
            height: 100px;
            background-color: skyblue;
            float: left;
        }

    
    </style>
</head>

<body>
    <div>
        <div class="box1">1</div>
        <div class="box2">2</div>
        <div class="box2">3</div>
    </div>
</body>

</html>